An annual inventory count tells you where you stood twelve months ago. For an aggregate operation moving material every day, that's not really inventory management — it's a once-a-year guess with eleven months of drift built in. A recurring aerial mapping program replaces that guess with a running, reconcilable record.

Why once a year isn't enough

Stockpiles at an active aggregate site change constantly — material comes in, gets crushed and screened, ships out, and shifts with weather and handling in between. An annual or semi-annual survey captures a single moment in a process that never stops moving, which means every reconciliation is really an attempt to explain twelve months of unmonitored change all at once. That's a hard position for operations to defend and a harder one for finance to sign off on with confidence.

Building the right flight cadence

There's no single right frequency — it depends on how fast material moves. High-throughput pits with daily truck counts often justify weekly flights, since that's the pace at which discrepancies would otherwise go unnoticed for too long. Slower-moving stockpiles can run on a monthly cycle, often timed to line up with financial close. Higher-value materials tend to justify tighter monitoring than bulk fill, simply because the dollar impact of a measurement gap is larger. For most sites, the right answer sits somewhere between weekly and monthly, set by production volume, reporting cycles, and material value — not by habit.

Reconciling volume against production records

A survey number is most useful next to the records it's supposed to agree with: scale tickets, crusher throughput, shipping logs. Applying a tested density factor converts surveyed volume into tonnage that can be compared directly against those production numbers, and flight-to-flight deltas that don't match expected extraction or shipping flag a discrepancy — whether that's a mis-recorded shipment, a measurement issue somewhere in the chain, or something that needs a closer look — while it's still a small number instead of a year-end surprise.

Choosing the right sensor for your site

Photogrammetry handles most open stockpile yards well and keeps flight and processing costs down, which matters when you're flying weekly. LiDAR earns its place on sites with real limitations for photogrammetry — shadowed pit walls, steep highwalls, dark or uniformly textured material that gives photogrammetry software little to work with, or active sites where airborne dust degrades photo quality. Some operations run photogrammetry for routine tracking and bring in LiDAR periodically for the harder-to-measure areas, which keeps ongoing costs reasonable without giving up accuracy where it's actually needed.

What makes the numbers trustworthy

Consistency does more for credibility here than raw accuracy alone. Using the same reference surface, the same density factors — checked and updated periodically through material testing rather than assumed indefinitely — and the same reporting format every cycle is what lets a finance team compare month three to month nine with confidence. A documented, repeatable methodology is also what turns a stockpile survey into something an external auditor can rely on, rather than a number they have to take on faith.

What each side of the business actually gets

Operations gets near-real-time visibility: what's on the ground right now for crusher feed planning, load-out scheduling, and blast planning, without waiting on a survey crew. Finance gets a defensible inventory valuation and a much shorter list of surprises at close. Those aren't competing priorities — they're two views of the same underlying data, which is exactly what makes a shared aerial mapping program more valuable than either team running its own separate process.

What to look for in a survey partner

A recurring program is only as good as its consistency, which makes the provider relationship matter more than it would for a one-off survey. Look for the same pilot or team flying the site whenever possible, a documented methodology that doesn't change flight to flight, and a provider who understands aggregate accounting well enough to deliver reports in the format your ERP or accounting system actually needs — not just a PDF that looks nice but has to be re-keyed by hand. The goal is a partner who treats the flight as step one of a data pipeline, not the whole job.

A note on multiple sites

Operations running more than one pit or yard face an added wrinkle: keeping methodology consistent across sites, not just across time at a single site. A density factor or reference surface convention that works at one location doesn't automatically transfer to another with different material or different equipment. Standardizing the survey approach across every site in a portfolio — same reporting format, same reconciliation cadence, same documentation standard — is what lets a regional or corporate finance team roll numbers up with confidence instead of reconciling several spreadsheets built several different ways.

What the first 90 days looks like

Most programs start with a baseline survey that establishes the reference surface every future flight will compare against. From there, the site settles into its flight cadence — weekly or monthly — for a full cycle before the first real reconciliation against production data. That first reconciliation is worth reviewing with both operations and finance in the room, since it's where the program either confirms it's tracking cleanly or surfaces the first real discrepancy worth investigating.